Objective: To identify in patients who survived 6 months after a spontaneous intracerebral haemorrhage (ICH) baseline characteristics and new clinical events associated with functional decline. Methods: In a single-centre study, we prospectively included 6-month survivors with a modified Rankin Scale (mRS) score 0-3. We defined functional decline by a transition to mRS 4-5. We evaluated associations of baseline characteristics and new clinical events with functional decline, using univariate and multivariable models. Results: Of 560 patients, 174 (31%) had an mRS score 0-3 at 6 months. During a median follow-up of 9 years (IQR 8.1-9.5), 40 (23%) converted to mRS 4-5. Age, diabetes mellitus, ICH volume and higher mRS scores at 6 months were independently associated with functional decline. Among baseline MRI markers, presence of strictly lobar cerebral microbleeds (CMBs), and mixed lobar and deep CMBs were independently associated with functional decline. When new clinical events occurring during follow-up were added in multivariable models, age (cause-specific HR (CSHR): 1.07; 95% CI: 1.03 to 1.11), ICH volume (CSHR: 1.03; 95% CI: 1.01 to 1.06), mRS score at 6 months (CSHR per 1 point increase 1.61, 95% CI 1.07 to 2.43), occurrence of dementia (CSHR: 3.81, 95% CI: 1.78 to 8.16) and occurrence of any stroke (CSHR: 4.29, 95% CI: 1.80 to 10.22) remained independently associated with transition to mRS 4-5. Interpretation: Almost one-fourth of patients with spontaneous ICH developed a functional decline over time. Age, ICH volume, higher mRS score at 6 months and new clinical events after ICH are the major determinants.